(a) Field
Embodiments of the invention relate to a charge pump and a switch control circuit.
(b) Description of the Related Art
A charge pump supplies power to a control IC, and for this purpose, the charge pump includes a capacitor. In general, when a switch of a power supply device is turned on, energy is stored from an input source of the power supply device to a charge pump. When the switch of the power supply device is turned off, energy that is stored at the charge pump is transferred to a power supply pin of a control IC.
In a general charge pump, because energy proportional to a line input voltage is stored, a power loss occurs according to a peak of the line input voltage. Further, in order to remove a ripple according to a line frequency, there is a problem that a capacitor of the charge pump that is connected to a power supply pin has a large size.
Further, as a ripple of an output current of a power supply device occurs, it is necessary to decrease the ripple of the output current.
Further, in a current mode control of a power factor correction circuit, when detecting an input voltage of the power factor correction circuit and directly using the detected input voltage, a start-up overshoot problem may occur in a high input voltage.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.